Announcing his decision, Trump thanked Herbert Raymond McMaster for his service, praising his “outstanding job” in his role as the National Security Advisor. McMaster “will always remain my friend,” the US president tweeted.

READ MORE: New NSC adviser John Bolton: The hawkiest hawk of the Bush administration?

“After thirty-four years of service to our nation, I am requesting retirement from the US Army effective this summer after which I will leave public service. Throughout my career it has been my greatest privilege to serve alongside extraordinary servicemembers and dedicated civilians,” McMaster said in a statement.

Trump reciprocated, noting that the general “served his country with distinction” for more than three decades. “General McMaster’s leadership of the National Security Council staff has helped my administration accomplish great things to bolster America’s national security,” the president said in a statement.

The administration especially noted McMaster’s crucial role in drafting the America First National Security Strategy, “smashing”Islamic State (IS, formerly ISIS/ISIL) terrorists and bringing North Korea “to the table.”

Bolton will become Trump’s third national security adviser in 14 months. McMaster was named Trump’s national security adviser in February 2017, just days after the US President sacked his predecessor, Michael Flynn, amid a scandal over his ‘unreported’ contact with the former Russian Ambassador to the US.

The White House has emphasized that Trump’s move to relieve the general of his duties was a mutually-agreed decision. “This was not related to any one moment or incident, rather it was the result of ongoing conversations between the two,” a WH official outlined.

Prior to Bolton’s official appointment, Trump had already hinted that the 69-year-old veteran war hawk will assume “a different” capacity. “I know John Bolton we’re going to be asking to work with us in a somewhat different capacity,” the US President said on Monday. “John is a terrific guy. We had some really good meetings with him. He knows a lot. He has a good number of ideas that I must tell you I agree very much with. So we’ll be talking to John Bolton in a different capacity.”

Bolton, who served as the head of the US delegation to the United Nations in 2005-2006, will assume his new role in April. The former Under Secretary of State for Arms Control and International Security (2001-2005) seems to have a unique vision on a wide range of national security issues. For instance, just last month, in an op-ed article in The Wall Street Journal, Bolton argued that there were no legal boundaries preventing the US from striking North Korea on grounds of ‘self-defense.’

On Thursday afternoon Donald Trump decided to sack Gen. HR McMaster from his national security adviser post, replacing him with John Bolton. The former US envoy to the United Nations will assume office on April 9 – just days after Mike Pompeo is set to replace Rex Tillerson as the new secretary of state.

READ MORE: Trump replaces national security adviser McMaster with John Bolton

The newly formed doublet has caused shockwaves among the Democrats [with whom, for once, I must 100% agree], who have alleged that Trump seems to be preparing for war. Democratic Senator from Massachusetts Ed Markey warned that Trump is creating a “war cabinet,” warning of “grave danger” following Bolton’s appointment.

“With the appointments of Mike Pompeo and John Bolton, @realDonaldTrump is successfully lining up his war cabinet. Bolton played a key role in politicizing the intel that misled us into the Iraq War. We cannot let this extreme war hawk blunder us into another terrible conflict,” he tweeted.

“John Bolton supports proactively bombing Iran & striking North Korea with nuclear weapons first without provocation. Appointing him to be Nat Sec Advisor is a grave danger to the American people & a clear message from @realDonaldTrump that he is gearing up for military conflict,” Senator Markey added.

The choice of Bolton as the national security adviser has also been questioned by Senator Jeff Merkley from Oregon, who has pointed out many flaws with the new appointee’s policies. “If you’re always wrong on security, you’re the wrong person to be National Security Advisor,” Merkley tweeted.

Rep. Barbara Jean Lee of California’s 13th congressional district was also disappointed by Trump’s choice, claiming she is hearing the “drumbeats of war.”

Fears expressed by some Capitol Hill members and the public seem justified. The notoriously hawkish former United Nations ambassador was a chief architect of the George W. Bush administration’s justification for the war in Iraq in 2003, that was based on false accusations that Baghdad possessed weapons of mass destruction.

Trump’s choice of Central Intelligence Agency (CIA) director Mike Pompeo as the new secretary of state also made many in Washington uneasy. Unlike his predecessor, Rex Tillerson, Pompeo seems better aligned with Trump’s confrontational foreign policy, namely on the Iran nuclear deal, on North Korea, and on the shift of the US embassy from Tel Aviv to Jerusalem. Besides politicians, the American public also expressed concern about the feasibility of a looming armed conflict.

Vermont Senator Bernie Sanders called Bolton “absolutely the wrong person to be national security advisor now,” recalling how he deceived the public about the Iraq war.

“John Bolton was part of the effort to mislead the US into the disastrous Iraq war and has supported military action against North Korea and Iran. He was too extreme to be confirmed as UN ambassador in 2005 and is absolutely the wrong person to be national security advisor now,” Sanders tweeted.

“John Bolton is a dangerous radical. President Trump’s decision to make Bolton his National Security Advisor is deeply disturbing,” Congressman Brendan F. Boyle (PA-13) said in a written statement. “John Bolton has spent his entire career pushing fringe conspiracy theories, espousing radical ideas about multilateralism, and undermining key alliances across the world.”